head and neck safety
10-13-2010, 09:24 AM
#61
Mr. Excitement
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Disingenuous Drive-by, it would seem?
Welcome to the Big Leagues.
There's something that I have been wondering about since he brought it up. I can only come up with scenarios in my head, so I need some expert counsel to critique my seat-of-the-pants theorizing. "The Professor" complains of the use of a dummy with a solid aluminum chest plate, and questions its relevance to a real human form and accurate testing results. If that is true, then I would agree, as far as that goes. However, understanding what Dr. Melvin refers to as "shape change" - the change in form of what becomes in reality a highly elastic human frame under the extreme loads of a crash - and understanding how this shape change allows occupants to slip out from between shoulder straps if they are too far apart (sternum projects forward, shoulders bend back, creating "belt slip ramps"), it seems to me that this solid chest plate would offer abnormally high retention rates by default because it did not allow this shape change to occur.
Applying this to the offset SFI test, my gut tells me that this solid alloy chest plate might actually "help" the situation where a HANS is concerned. I can create a theory where the solid chest plate would act like a lever when belt force was applied to the shoulder nearest the impact, forcing the far shoulder more solidly into the HANS/belt than would be the case with a highly elastic human torso. If this were the case, I might not wonder if it increased the pressure on the far shoulder, increasing potential retention at the same time. Assuming he is correct about this artificial dummy, has anyone ever thought of my theory before, if it is even relevant?
Welcome to the Big Leagues.
There's something that I have been wondering about since he brought it up. I can only come up with scenarios in my head, so I need some expert counsel to critique my seat-of-the-pants theorizing. "The Professor" complains of the use of a dummy with a solid aluminum chest plate, and questions its relevance to a real human form and accurate testing results. If that is true, then I would agree, as far as that goes. However, understanding what Dr. Melvin refers to as "shape change" - the change in form of what becomes in reality a highly elastic human frame under the extreme loads of a crash - and understanding how this shape change allows occupants to slip out from between shoulder straps if they are too far apart (sternum projects forward, shoulders bend back, creating "belt slip ramps"), it seems to me that this solid chest plate would offer abnormally high retention rates by default because it did not allow this shape change to occur.
Applying this to the offset SFI test, my gut tells me that this solid alloy chest plate might actually "help" the situation where a HANS is concerned. I can create a theory where the solid chest plate would act like a lever when belt force was applied to the shoulder nearest the impact, forcing the far shoulder more solidly into the HANS/belt than would be the case with a highly elastic human torso. If this were the case, I might not wonder if it increased the pressure on the far shoulder, increasing potential retention at the same time. Assuming he is correct about this artificial dummy, has anyone ever thought of my theory before, if it is even relevant?
Big leauges? An internet car forum is Big leagues?
Well...
That would certainly represent a more real world scenario, but it also enters other variables into the mix that cannot necessarily be factored out, and probably would color the outcome of the data and performance of the product in question to some degree. I'd guess they use a "church pew" to get a very clear idea of the exact performance of the device being tested, and only that.
That would certainly represent a more real world scenario, but it also enters other variables into the mix that cannot necessarily be factored out, and probably would color the outcome of the data and performance of the product in question to some degree. I'd guess they use a "church pew" to get a very clear idea of the exact performance of the device being tested, and only that.
This is not a place or area for taking sides. This is an area for real science and work for advancement in driver safety. Petty jabs by ax grinders , while not uncommon, are unbecoming in a professional and scientific discussion. HANS opened the door to advanced H&N safety. This does not mean that the first is the best nor does it mean they are the bad guys. How about some unbiased discussion?
10-13-2010, 09:28 AM
#62
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"sales hack"
Are you serious gbaker? You are actually going to put down a profession? Maybe if you had a little professional sales help, you wouldn't have such a small percentage of the market.
Howard Bennett
Are you serious gbaker? You are actually going to put down a profession? Maybe if you had a little professional sales help, you wouldn't have such a small percentage of the market.
Howard Bennett
10-13-2010, 09:35 AM
#63
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I only see one problem with the Isaac which is the only reason I don't use one anymore. I don't know of any professional level datalogging that shows real world crashes and surviveability. We have dozens of HANS crashes with data from the pros like the indy guy that hit the catch fence over 100g's about 4 years ago and the schumacher 100+G crash at indy are 2 HANS crashes I can think of. Those kinds of crashes prove the device and proves the theory. So even if the newtons on the head are higher with the HANS than the Isaac we know that the HANS is working under the conditions that it needs to work. Unfortunately, no pros are going to use the Isaac because the sanctioning bodies want SFI38.1 and FIA for what that is worth, so we are never going to get beyond Isaacs perfect engineering to see what happens in real life with real data. Unfortunately, me still being alive flipping my Ferrari into a wall wearing a HANS with sketchy data does not support the product.
I agree with what you are saying, and yet your examples also "prove" my point about using the church pew for the test. My estimation has always been that the HANS was designed with an open wheel cockpit in mind, even though I know Mr. Downing as a sports car racer. Those cockpits in their most modern form are closed to much of any head movement except forward. This plays right along with the HANS, as it is a device that works very well in a straight forward direction, but is intuitively "marginalized" in an offset environment. If the SFI test that Isaac ran is any real indication (the one we are speaking of here recently), then it is also "marginal" in practice as well.
It's a shame that the Isaac has been "marginalized" by factors other than its performance, but the dust bin of history is filled with "better" ideas that never caught on for reasons far removed from their intrinsic worth.
10-13-2010, 10:56 AM
#64
Mr. Excitement
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NASCAR is open cockpit? In this very thread someone brushed aside 4000 real world impacts with no reason to think the Hans brand device did not work as intended. Full containment seats were not invented just to make the Hans brand device work better they make the entire system work better. Not all NASCAR seating systems are the same ether. I am not saying that one H&N is better than the other only that the hard metal bench and a tin man has no bearing at all on how ether device is ever used. It would not be too hard for some to call that cooked data. How about setting up a seating system per the min standards set by the seller in their enclosed paperwork and test? That just might be a better test of a system.... in use as intended.
10-13-2010, 11:40 AM
#65
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R3 FIA Approval, FIA specs for HNR's, 2010 Helmet Anchors
The Safety Solutions Model R3 has been approved by the FIA. Note FIA approvals are date and serial number specific, so if you're racing in Europe make sure your R3 was manufactured after the approval date or it will not qualify for certification. Also, only the R3 has been certified - the Hybrid, Hybrid X and Hybrid Pro are not FIA certified at this point in time.
Regarding your other questions, the FIA have written new specs specifically for the R3 product - it's called FIA 8858:2010. As the HANS Device was the only HNR available when the old standard was published (2002) you are correct that the physical/dimensional parts of that standard related only to HANS. But the performance characteristics are the same.
Regarding the 2010 anchor photo, SAH 2010 helmets will come with the nutwasher for the head and neck restraint bonded into the helmet. We have developed three anchors that meet this spec. Two have passed their FIA tests and one is pending. We will have a version of our standard post anchor that is backwards compatible with every HANS ever made, a new Quick Click that is half the size and weight of our existing QC, and a version of our permanent LW2 lightweight anchor.
Finally regarding Kubica's belts, have you ever seen a major car wreck? After the wreck EVERYTHING is all over the place. Belts come off the driver, let alone his safety gear. Helmets come off. Lateral head restraints bend, nets stretch etc. The BMW F1 team issued a press release saying the HANS Device saved Robert's life. You can clearly see it working during the accident (at several different points). I guess his fire suit was wrinkled after the impact too, does that mean it didn't do it's job? My point is these impacts happen in milliseconds and there is nothing to be gained by discussing what happened half a minute after the impact - the event is over by then.
I can't seem to attach photos of our new anchors but I'll try again in another post.
Regarding your other questions, the FIA have written new specs specifically for the R3 product - it's called FIA 8858:2010. As the HANS Device was the only HNR available when the old standard was published (2002) you are correct that the physical/dimensional parts of that standard related only to HANS. But the performance characteristics are the same.
Regarding the 2010 anchor photo, SAH 2010 helmets will come with the nutwasher for the head and neck restraint bonded into the helmet. We have developed three anchors that meet this spec. Two have passed their FIA tests and one is pending. We will have a version of our standard post anchor that is backwards compatible with every HANS ever made, a new Quick Click that is half the size and weight of our existing QC, and a version of our permanent LW2 lightweight anchor.
Finally regarding Kubica's belts, have you ever seen a major car wreck? After the wreck EVERYTHING is all over the place. Belts come off the driver, let alone his safety gear. Helmets come off. Lateral head restraints bend, nets stretch etc. The BMW F1 team issued a press release saying the HANS Device saved Robert's life. You can clearly see it working during the accident (at several different points). I guess his fire suit was wrinkled after the impact too, does that mean it didn't do it's job? My point is these impacts happen in milliseconds and there is nothing to be gained by discussing what happened half a minute after the impact - the event is over by then.
I can't seem to attach photos of our new anchors but I'll try again in another post.
10-13-2010, 11:49 AM
#67
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For the record, Isaac has never run any tests. We contract with labs to run test protocols that were designed by others. The lab technicians then follow the protocols, which incorporate the manufacturers' instructions for all products. In the case of the videos referenced here, the test protocol is per SFI spec 38.1 performed by Delphi Safety Systems and the belts and HANS device were installed per HANS instructions. This is standard lab procedure, otherwise the test is worthless.
You guys are aware of belts coming off and drivers being trapped in burning cars in race settings, right? Especially road racing?
You guys are aware of belts coming off and drivers being trapped in burning cars in race settings, right? Especially road racing?
Last edited by gbaker; 10-13-2010 at 04:25 PM.
10-13-2010, 11:56 AM
#69
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<quote> the HANS device may indeed have a problem staying under the harnesses. If the test you refer to above is the one I am thinking of (I have the video clip), and is not valid, then it is Delphi and the SFI you will have to seek redress from, </quote>
The test I believe you refer to shows the belts coming off the device around the 10 second mark. The test is over at the 100 milliseconds mark. As I said in my previous post a great many things happen as a crash winds down. For instance the belts stretch a large amount as they do their job. Seats move, roll bars bend, helmets move and come off, fireproof clothing and tethers shrivel up. Does that mean none of the stuff works, or does that mean it's doing its job correctly? I'm sure you can figure that out.
The test I believe you refer to shows the belts coming off the device around the 10 second mark. The test is over at the 100 milliseconds mark. As I said in my previous post a great many things happen as a crash winds down. For instance the belts stretch a large amount as they do their job. Seats move, roll bars bend, helmets move and come off, fireproof clothing and tethers shrivel up. Does that mean none of the stuff works, or does that mean it's doing its job correctly? I'm sure you can figure that out.
10-13-2010, 12:00 PM
#70
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The Safety Solutions Model R3 has been approved by the FIA. Note FIA approvals are date and serial number specific, so if you're racing in Europe make sure your R3 was manufactured after the approval date or it will not qualify for certification. Also, only the R3 has been certified - the Hybrid, Hybrid X and Hybrid Pro are not FIA certified at this point in time.
Regarding your other questions, the FIA have written new specs specifically for the R3 product - it's called FIA 8858:2010. As the HANS Device was the only HNR available when the old standard was published (2002) you are correct that the physical/dimensional parts of that standard related only to HANS. But the performance characteristics are the same.
Regarding your other questions, the FIA have written new specs specifically for the R3 product - it's called FIA 8858:2010. As the HANS Device was the only HNR available when the old standard was published (2002) you are correct that the physical/dimensional parts of that standard related only to HANS. But the performance characteristics are the same.
Here is the FIA standard showing the Hybrid is the device.
http://argent.fia.com/web/fia-public.nsf/782C162EC4681517C1257760005B9C4D/$FILE/8858-2010_Frontal_Head_Restraint.pdf
10-13-2010, 12:17 PM
#71
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I apologize for my error. As they sell three devices labelled Hybrid make sure you get the right one if you need to race with it in Europe. Thanks for your correction Joe.
10-13-2010, 01:23 PM
#72
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As defined by what, exactly? The test spec?
I'd have to check my data, but I'm pretty sure my last few crashes have lasted longer than 100ms.
As far as bench seat, etc, relating to/changing results... it shouldn't take an engineering degree to realize that the specifications for the testing performed, being run as an experiment, are an effort to isolate the variables to those of interest.
As it is clear that seat config, etc, even belt tension, can and will dramatically affect results, those variables should be fixed by the test protocol to allow us to focus on only the variables of interest - performance of the H+N restraint under standard conditions.
That's just good experimental procedure, not marketing voodoo.
PS: Lies, Damn Lies, and Statistics.
10-13-2010, 01:59 PM
#73
This is not a place or area for taking sides. This is an area for real science and work for advancement in driver safety. Petty jabs by ax grinders , while not uncommon, are unbecoming in a professional and scientific discussion. HANS opened the door to advanced H&N safety. This does not mean that the first is the best nor does it mean they are the bad guys. How about some unbiased discussion?
10-13-2010, 06:01 PM
#74
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I have to agree that for the average guy who doesn't have a degree in Biomechanics etc...all this talk makes the decision process more clouded.
Is there at least some sort of nodding of heads that having the 'shock absorber' style of restraint does make some sense? Rather than just having a piece of tether that stops your head moving past a certain point, this seems to be a valid idea? What about shock failure? Does this happen? Can a tether fail? A lot less to it, so perhaps it's almost unbreakable?
The thing is that going from not having any head and neck restraint to entering the marketplace, I find all these discussions a bit daunting. You feel like you don't want to buy the wrong article so you actually don't buy anything.
Is there at least some sort of nodding of heads that having the 'shock absorber' style of restraint does make some sense? Rather than just having a piece of tether that stops your head moving past a certain point, this seems to be a valid idea? What about shock failure? Does this happen? Can a tether fail? A lot less to it, so perhaps it's almost unbreakable?
The thing is that going from not having any head and neck restraint to entering the marketplace, I find all these discussions a bit daunting. You feel like you don't want to buy the wrong article so you actually don't buy anything.
10-13-2010, 07:56 PM
#75
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As I noted a few years ago, watch the video on the Isaac site. But dont look at the HANS side, watch the Isaac side of the video. After the impact, the Issac device is now IN FRONT of the driver on the upper portion of his chest. Not good for multiple impacts in my eyes.
Thats what sold me on the R3.
Don't listen to me, just watch it yourself.
Thats what sold me on the R3.
Don't listen to me, just watch it yourself.